It’s just one short block of Bergen Street in Prospect Heights, but the guerrilla bike lane birthed by local resident Ian Dutton has become an object lesson in the conflict between NYPD’s use of street space, on the one hand, and New Yorkers’ safety on the other. On Saturday, when BrooklynSpoke’s Doug Gordon snapped this photo, the bike lane was functioning beautifully, with orange posts keeping it free from encroachment by the nearby 78th Precinct.

The next day, with the posts shifted a few feet to the right, police had once again taken over the bike lane to store a squad car. Anyone riding by on this major bike route would have to swerve into traffic.

Cops parking where they don’t belong is hardly limited to this spot. The city’s sidewalks, bus lanes, bike lanes, and general traffic lanes are routinely obstructed by squad cars or placarded vehicles. The notable thing about this piece of DIY street engineering is that it has compelled police to take an extra, willful step to appropriate the public right-of-way. The street was functioning fine, thanks to a few well-placed plastic sticks, but apparently a functional street only lasts so long next to a precinct house.